Compressor



Feb. 7 23, '1932. F. J: RAYFIELD 1,846,655

COMPRESSOR Filed Nov. 15, 1929 3 Sheets-Sheet 1 fiederidn/ Hay/laid Feb. 23, 1932. F. J. RAYFIELD 1,846,555

COMPRESSOR v V File d Nov 15,- 1929 3 Sheets-Sheet 2 52 x 55 58 DI 40 H u y 29 .1 I. 1 I? I Ii" 7 29 5! 5 I II {ga g I I v 'I I I; WW I l r 5 I F, a v I f I fiederic J Bay/424d Feb. 23, 932.

F; J. RAYFIELD' Couransson Filed Nov. 15,1929

3 Sheets-Sheet 3 Patented Feb. 23, 1932 UNITED STATES 'WPATENT OFFICE FREDERICK J. RAYFIELD, OF CHICAGO, ILLINOIS, ABSIGNOR CHAMPION PNEUMATIC MACHINERY 00., OF CHICAGO, ILLINOIS, CORPORATION OF ILLINOIS oomrnns'soa Application filed November 15, 1929'. Serial No. 407,388.

to provide a self-contained compressor unit for furnishing large volume of air at high pressure.

Another important object is to so arrange a plurality 'of large'bore and small bore cylinders around a common crank-shaft so that a very compact-structure will result, and so that there will; be uniform distribution of impulse and flow, resulting in the reduction of vibration to a minimum.

low pressure cylinders in pairs around the crank-shaft with the cylinders offset sufficiently on the crank-case to permit the use of. straight connecting rods and with each rod having its own bearing on the crank-shaft.

Another important object is to provide domed cylinder heads with correspondingly domed pistons, and to discharge the air from the center of the domed cylinder heads,

thereby keeping the cylinder heads cool and preventing pounding. v

A further object is'to assist the cooling of the cylinder head by providing radiating fins thereon and by providing fan vanes of large capacity on the fly wheel on the crank-shaft On the drawings:

- for applying large volumes of cooling air .to

the fins during operation of the compressor.-

The above enumerated features and other features of my invention are exemplified in pin 17 and the small piston has a wrist pin 18. The wrist pin of the large cylinder the structure shown on the drawings.

. Figure 1 is a side elevation of my improved compressorunit;

Figure 2 is a plan view of the unit; Figure 3 is an enlarged-section 'on plane IIIII,I of Figure 2; a i

Figure 4 is an enlarged section o'nplane IV- -IV of Figure 3; and I I 1 Figure 5 is an enlarged section through one ofthe fittings for connecting a low researc 7 cylinderjwith a high pressure cylin er.

As shown onthe drawings: The unit comprises a supporting base 1, a compressor structure C and a motor M. The

dri inmotor for the'compressor'may be a A further object is to arrange the high and gasoline engine or, as shown, may be an electric motor. The reservoir 2 isshown as of cylindrical shape and is supported upon suit-- able standards 3. The base 1 of the unit may be in the form of a channel iron resting on and secured to the top of the reservoir 2, and the entire outfit thus forms a verycompact.

structure.

. The compressor structure comprises a base a which may be in the form of a casting and which is mounted on and secured to the supporting channel 1. The crank-case 5 of the compressor structure is mounted on and detachably secured to the base 4, and on the crank-case are mounted and detachably secured two pairs of cylinder structures, each comrising a large bore cylinder 6' and a sma l bore cylinder 7 the cylinders preferably forming part of an integral casting.

The cylinder pairs are preferably offset from the vertical axis of the compressor, or, in other words, they are spaced 90 apart on the upper part of the crank case. The bores 8 and 9 of the cylinders 6 .and'7 communicate at their lower ends with the interior case and hascrank sections 13 and 14 displaced 180.

The large bore cylinder of ea ch cylinder structure has-a iston 15, and the associated smallbore cylin er has a piston 16. The large piston of-each cylinder structure has a wrist of one pair is connected bya connectin rod 19 with the crank shaft section 13, whi e its associated smallpiston is connected by a rod 20 with the crank section 14. As best shown in Figure 3, the'large cylinder of the other pair has, its piston connected by the rod 21 .with theicrank section 14 and its smaller pisreceives the connecting rod of. the large piston of one cylinder structure and. the connecting rod of the small piston of the othercylinder structure. As best shown in Figure 2, the cylinders of each pair are offset sufficiently to permit the use of straight connecting rods, the rods being preferably of the I-beam type. The described arrangement of the cylinders and their connections with the crank shaft produces smooth and balanced running and reduces vibration to a minimum.

The upper ends 15 of the large pistons are frusto-conical or dome-shaped, and the upper ends 8 of the large cylinders are correspondingly shaped to receive such piston ends. The upper ends 16 of the smaller pistons are also frusto-conical or dome-shaped and the upper ends 9' of the respective cylinders are correspondingly shaped to receive the pistons when at the ends of their in-strokes. The inlet passage 23 for each large cylinder is concentric with its domed upper end and presents a seating shoulder 24 for a suitable check valve structure 25. Likewise, the outlet 26- for each small cylinder is concentric with the domed end of the cylinder and presents a seating shoulder 27 for a suitable check valve structure 28.

An air inlet pipe 29 is secured by a flange 30 above the inlet passage 23 for each of the large cylinders, and the inlet valve structure 25 is secured between such flange and the supporting shoulder 23. Each pipe 29 terminates at its outer end in an air filter structure 31 for cleaning the air before'it is drawn into the large cylinder. The large cylinder of each pair has an outlet passage 32 extending laterally from the domed end of the cylinder, and inthis passageway is seated a suitable check valve 33. The small cylinder of each pair has an inlet opening 34 extending'laterally at its domed end and in such inlet passage is a suitable check valve 35. A U-shaped pipe or conduit 36 connects the outlet of the large cylinder of each pair with the inlet of the associated small cylinder, the pipe having suitable coupling flanges 37 and 38 whereby it may be detachably secured to the respective cylinders. A discharge pipe 39 is secured by a flange 40 to each small cylinder to communicate with the outlet thereof, and each pipe is connected by a fitting 41 with the chamber 42 within the base 4. In each cylinder structure the large cylinder takes in air through the filter 31 and then gives the indrawn air an initial compression, the compressed air flowing through the pipe 36 to the associated smaller cylinder, where it is given a final compression, and is discharged through the pipe 39 into the chamber 42. In the arrangement shown, each quarterturn of the crank-shaft starts a compression stroke, the distribution of impulse and load being uniform, so that smooth and balanced operation results and vibration is reduced to a minimum.

The air discharged into the chamber 42 is flow of compressed air from the reservoir to the compressor when the com ressor is idle.

The compressed air is fed rom the reservoir into a housing 44, from which extends any number of service pipes 45 for conducting the compressed air to the points of consumption. A pressure gauge 47 and a safety valve 48 may be connected with the pipe 44. Within the housing 45 may be suitable switch mechanism (not shown in detail) which may be automatically controlled by the pressure in the reservoir to disconnect the motor M from circuit when the pressure in the reservoir reaches a predetermined maximum limit, and to connect the motor in circuit when the pressure falls below a predetermined minimum.

On the outer end of the crank-shaft is supported a drive pulley 49 connected by belts 50 with the motor M. The pulley is of large enough diameter so that its rim extends radially beyond the compressor cylinders, and the spokes of the pulley are extended to form vanes or blades 51 of substantial area and capacity so as to throw a large volume of air against the cylinders when the compressor is operating. The cylinders preferabl have radiator fins or flanges 52, so that t e heat of compression is rapidly conducted away from the cylinder walls and carried away from the extensive surface of the fins by the air propelled by the fan vanes. The vanes are at the outer ends of the spokes of the pulley so that practically all of the air impelled thereby is applied to the cylinder walls to effect cooling. These vanes also add weight to the pulley so that it will act as a fly-wheel for the compressor.

It will be noted that the compressed air is discharged from the center of the domed ends of the high pressure cylinders. This arrangement produces a smoother and more balanced operation of the pistons and also greatly reduces the tendency to pounding. The friction of the piston operation is also materially reduced, thus keeping down the temperature.

The arrangement and connection of the cylinders could be varied. For example, the large cylinders could all be on one side and the smaller cylinders on the other side of the crank-case, and the cylinders could be cross connected as desired. Other changes and modifications could also be made without departing from the spirit and scope of the invention, and I do not desire to be limited except as necessitated by the prior art.

I claim as follows:

1. In a compressor structure, the combination of a crank case, a crank shaft, two pairs of compression cylinders mounted on said crank shaft, a low compression and a high compression cylinder for each pair, the cylinders for each pair being oflset in opposite directions from the vertical plane of the crank shaft axis, pistons for said cylinders, piston shaft, and a U-shap pair of cylinders connectlngrods connecting said istons with said crank conduit of large crosssection for each the low compression cylinder with the high compression cylinder'thereof, said conduits extending towards each other between said cylinder pairs to be concentric with said shaft.

2. In a compressor structure, the combination of a crank case, a crank shaft, two pairs of compression cylinders mounted on- 'said crank case and ofiset in opposite directions from the vertical plane of said crank shaft axis, .a low compression and a highcompres sion cylinder .zlfor each pair, pistons for said cylinders, p1ston rods connecting said pistons with said crank shaft, a U-shaped conduit of large cross-section for each pair connecting the low compression cylinder with the high compression cylinder thereof, said U- shaped conduits extending towards each other between said pairs to be concentric with said shaft, and a combined flywheel and fan on said crank shaft adjacent to said cylinder and conduits for blowing cooling air current across said cylinders and conduits.

In testimony .whereof I have scribed my name at Chicago, Cook County,

Illinois.

FREDERICK J RAYFIELD.

hereunto sub- 

